Complete public pricing page showing all 4 subscription plans (FREE,
AGENT_PRO, INVESTOR, ENTERPRISE) with billing cycle toggle, feature
comparison table, VND formatting, and Vietnamese/English i18n support.
Also adds pricing link to public navigation header and footer.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Add locale-prefixed routes for admin, auth, dashboard, and public pages.
Add error, loading, and not-found pages for locale context. Add language
switcher UI component for Vietnamese/English toggle.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
